Quantum Gas of Deeply Bound Ground State Molecules

by J. G. Danzl, E. Haller, M. Gustavsson, M. J. Mark, R. Hart, N. Bouloufa, O. Dulieu, H. Ritsch, H.-C. Nägerl
Abstract:
Molecular cooling techniques face the hurdle of dissipating translational as well as internal energy in the presence of a rich electronic, vibrational, and rotational energy spectrum. In our experiment, we create a translationally ultracold, dense quantum gas of molecules bound by more than 1000 wave numbers in the electronic ground state. Specifically, we stimulate with 80% efficiency, a two-photon transfer of molecules associated on a Feshbach resonance from a Bose-Einstein condensate of cesium atoms. In the process, the initial loose, long-range electrostatic bond of the Feshbach molecule is coherently transformed into a tight chemical bond. We demonstrate coherence of the transfer in a Ramsey-type experiment and show that the molecular sample is not heated during the transfer. Our results show that the preparation of a quantum gas of molecules in specific rovibrational states is possible and that the creation of a Bose-Einstein condensate of molecules in their rovibronic ground state is within reach.
Reference:
Quantum Gas of Deeply Bound Ground State Molecules,
J. G. Danzl, E. Haller, M. Gustavsson, M. J. Mark, R. Hart, N. Bouloufa, O. Dulieu, H. Ritsch, H.-C. Nägerl,
Science, 321, 1062–1066, 2008.
Bibtex Entry:
@article {Danzl1062,
	author = {J. G. Danzl and E. Haller and M. Gustavsson and M. J. Mark and R. Hart and N. Bouloufa and O. Dulieu and H. Ritsch and H.-C. N{"a}gerl},
	title = {Quantum Gas of Deeply Bound Ground State Molecules},
	volume = {321},
	number = {5892},
	pages = {1062--1066},
	year = {2008},
	doi = {10.1126/science.1159909},
	publisher = {American Association for the Advancement of Science},
	abstract = {Molecular cooling techniques face the hurdle of dissipating translational as well as internal energy in the presence of a rich electronic, vibrational, and rotational energy spectrum. In our experiment, we create a translationally ultracold, dense quantum gas of molecules bound by more than 1000 wave numbers in the electronic ground state. Specifically, we stimulate with 80% efficiency, a two-photon transfer of molecules associated on a Feshbach resonance from a Bose-Einstein condensate of cesium atoms. In the process, the initial loose, long-range electrostatic bond of the Feshbach molecule is coherently transformed into a tight chemical bond. We demonstrate coherence of the transfer in a Ramsey-type experiment and show that the molecular sample is not heated during the transfer. Our results show that the preparation of a quantum gas of molecules in specific rovibrational states is possible and that the creation of a Bose-Einstein condensate of molecules in their rovibronic ground state is within reach.},
	issn = {0036-8075},
	URL = {https://science.sciencemag.org/content/321/5892/1062},
	eprint = {https://science.sciencemag.org/content/321/5892/1062.full.pdf},
	arxiv = {https://arxiv.org/abs/0806.2284},
	journal = {Science}
}